ABSTRACT This Center grant requests funding for six core facilities; Administrative, Clinical/Translational, Cellular Imaging, Mouse Neurodevelopmental Behavior, Mouse Gene Manipulation and Molecular Genetics, to support a broadly-based research program in intellectual and developmental disabilities at Boston Children's Hospital and Harvard Medical School. Our specific aims are to: 1) Maintain and introduce new ?state of the art? core facilities that can be shared by Intellectual and Developmental Disabilities Research Center (IDDRC) investigators, providing core research services not possible in a single laboratory; 2) Use the framework of the core laboratories to enhance and encourage collaboration between IDDRC investigators; 3) Provide core services to aid in the training of young investigators and trainees and 4) Use the core services provided by the IDDRC program to leverage collaboration outside the institution, particularly with other IDDRCs, to speed the development of effective clinical interventions in intellectual and developmental disabilities. The Center supports 105 research projects and 64 investigators who receive approximately $71M in external funding, $46M of which is from the NIH. Research in the Center occurs in over 125,000 sq.ft. of space in research buildings at Boston Children's Hospital and Harvard Medical School affiliated institutions in the Harvard Longwood Medical Area. Our research focuses on three programmatic areas- Basic Neuroscience, Clinical / Translational Neuroscience and Genetics- and our primary goal is to identify the causes of and develop therapies for children with intellectual and developmental disabilities. The research of this IDDRC encompasses laboratory research on fundamental processes of normal and abnormal neurodevelopment and plasticity, as well as clinical and behavioral studies directed at disorders including, but not limited to, autistic spectrum disorders, brain injury, neuro-oncology, learning and cognitive disabilities, the effects of surgery and environmental toxins on neural development, and multiple neurogenetic disorders, including those that affect neural formation, migration, specification and synaptic connectivity, as well as muscular dystrophy.